In joining two sheets of metal together with fasteners such as self drilling threaded fasteners, difficulties arise in that on the fastener passing through a first sheet and engaging an unsupported second sheet, that the unsupported second sheet may deflect away on engagement with the screw. Such difficulties particularly arise when joining together metal framing comprising U-shaped channel members of sheet metal where overlapping portions of the U-shaped channel members are desired to be joined together with screws.